IIRC, most of the damage from that recent event was windows shattering. Unless you have a dedicated blast shelter to go, to that's probably your best move.BTW, when I see bright flashes in the sky, I've trained myself to get behind something to avoid my skin catching fire, and then run to some substantial cover in the interval between the flash and the blast wave. Very cool looking until your retinas dissolve.

It's not gravity that's the problem - it's air resistance. Earth's atmosphere doesn't have a distinct edge, and you have to get pretty frelling far out before the particle count drops low enough not to matter to things going 10,000+mph. Certainly a lot farther than the measly few dozen miles to low Earth orbit.

It's not gravity that's the problem - it's air resistance. Earth's atmosphere doesn't have a distinct edge, and you have to get pretty frelling far out before the particle count drops low enough not to matter to things going 10,000+mph. Certainly a lot farther than the measly few dozen miles to low Earth orbit.

Well the orbital path does make large parts of the globe safe.

That is why Carly and I are flying my jet to Nova Scotia just to be safe.

What Immerman said. A satellite deals with gravity just peachy, but air kills it.

No artificial satellite is completely outside the atmosphere. There are still traces of air even hundreds of miles out, and every time a satellite hits an air molecule it loses an eensy-teensy bit of energy. Each loss makes the orbit a little bit lower, and a little bit faster. (Yes, orbital mechanics is a curious realm where you can slow down by applying thrust and speed up by applying the brakes.) The lower it gets, the more often it hits a molecule, and the energy loss gradually begins to snowball.

You can't predict the precise impact point without precise knowledge of the air density the satellite is encountering, and we don't have that information because it varies with all manner of factors, like solar wind and terrestrial weather. The principal means of prediction is the change in the length of an orbit. When you start seeing a measurable time difference from one orbit to the next, things are starting to happen.At that point, you can predict the time of impact with a precision on the order of weeks, and as time goes on you can narrow it down further.

Right now, we know when GOCE will come in give or take a handful of hours -- and since it can circle the world a couple of times in that interval, we have very little idea of where it will hit. As time passes, the error factor shrinks...when Skylab came in, NASA knew it would hit "somewhere in Australia" three or four hours before it hit.

An intentional reentry is different, because you use a retro-rocket to dump a nice big packet of energy and skip right over the protracted decay time, and make it land where you want.

In the interest of perspective, keep in mind that Nature throws rocks at us from space all the time -- meteors big enough to survive the trip through the atmosphere hit the earth dozens of times per day. Yet there are only a handful of cases on record where a person was injured, or even saw one hit -- simply because you and I and all the other people cover a VERY tiny fraction of the earth's surface. We are little bitty spots on a great big dartboard.

Which is why I don't understand they let it come down uncontrolled. Wasn't there all this hubbub when ROSAT and Phobos Grunt came down that satellites should have a final fuel supply left to do a controlled de-orbit? And here is GOCE which has engines and at the end of its lifespan was even lowered to make better science... and they let it de-orbit uncontrolled.

Wasn't there all this hubbub when ROSAT and Phobos Grunt came down that satellites should have a final fuel supply left to do a controlled de-orbit? And here is GOCE which has engines and at the end of its lifespan was even lowered to make better science... and they let it de-orbit uncontrolled.

The engine on GOCE was a little ion engine. Not enough thrust to predictably de-orbit where you are aiming. And it was designed prior to the new guidelines that satellites should safely de-orbit, unfortunately.

Whoever it lands on will certainly get the ultimate lesson in gravity.

Yes, it would be a grave situation.

If anyone seriously thinks this is a threat, buy a lottery ticket.

I saw a really weird shooting star once while traveling. It was shooting upwards, was a really bright green, and flashed as it went.

The next day I read in the paper that the Russians had thrown a very large old computer out of the MIR. This one ought to be a hell of a shooting star if it comes down at night anywhere where anyone can see it

I saw a really weird shooting star once while traveling. It was shooting upwards, was a really bright green, and flashed as it went.

It sounds like you might have witnessed upper-atmospheric lightning [wikipedia.org]. If you're unfamiliar with these phenomena, please see some of the rare* videos that have been captured. Although it might** have been MIR's jettisoned computer, (which might explain the green color (i.e., burning copper wire)), UAL would account for both the color and the upward trajectory.

* Although witnessed for decades by pilots, their stories had been dismissed. UAL has only recently been recognized as being "real," and research is in

If it lands in the US, it could be considered a lawsuit.If it lands on South Korea, it could be construed as a blow from the Sacred Unicorn of the North.If it lands in Russia, it will end up on You Tube for weeks.

manslaughter, involuntary(debatable if it's unplanned I suppose, since they knew it would land somewhere when they shot it up) homicide - but technically yes.

however, if you can't get them on trial for intentional killings done by bombs dropped from the sky on civilians - in a country with which they are not in war with, which doesn't have warzone status by any definition.. how the fuck could you get anyone on the hook for this? "it was just a bomb that was supposed to hit a terrorist but which unfor

"The octagonal, 1100-kg satellite with a cross-sectional area of only 1m is configured to keep aerodynamic drag and torque to an absolute minimum. GOCE is symmetrical about its flight direction and two winglets provide additional aerodynamic stability. "

She might just penetrate like a spear, with the front burning away as she slows down. Sounds like she's built very solidly as well. So we should still have a nice big solid chunk of debris for impact. Possibly even salvageable for the museums!

But I'm afraid sleeping in your basement won't make a whole lot of difference.

You see, in English language basically everything that can't run away and hide up on a tree on its own is considered female.
And this thing is even flying towards us, which qualifies double, especially for slashdotters.

Metal doesn't burn easy, and this is likely moving a *lot* slower than most iron meteors that manage to burn up anyway. Most likely any antennas and other large surfaces will be ripped off by the hot ionized plasma "wind" of reentry, and the main structure itself may be break up as well. But that'll be chaos in action, hard to predict beforehand.

Some, but not all of it. http://www.spaceflight101.com/goce-re-entry.html [spaceflight101.com] :
With its fins and aerodynamic shape, GOCE will maintain a stable position in orbit as it approaches entry. During entry, the spacecraft will likely remain in that position for the initial phase of re-entry until it breaks up. Following the destruction of the spacecraft, most of its components will harmlessly burn up in the atmosphere.
However, it is known that about 20 to 40% of a re-entering satellite's total mass reach Earth's surface. Dense components of satellites usually impact 800 to 1,300 Kilometers downrange from the Orbital Decay Point. Their journey back to Earth is strongly influenced by atmospheric properties like crosswinds that play a major role during atmospheric descent.

and http://www.spacesafetymagazine.com/2013/09/14/european-satellite-goce-uncontrolled-reentry/ [spacesafetymagazine.com]
his will be the first uncontrolled reentry of an ESA satellite since Isee-2, in 1987. Unfortunately, it will not be the last, considering that the bus-size Envisat’s altitude is gradually decaying in Low-Earth Orbit without control. According to ESA, up to 25% of GOCE’s mass will survive the extreme reentry conditions to fall to the ground. However, the risk for populated areas is very small since the majority of the Earth is covered by oceans.
“The major part of what survives to the surface will be the core instrument,” says Dr. Floberghagen. “From the original mass which we have now in space, we have estimated that about 25%, about 250 kilos, will reach the surface, and these 250 kilos will be distributed over between 40 and 50 fragments.”
The fragments that survive will hit the ground in a 900 km long footprint. The reentry will be a good test for debris monitoring systems and fragmentation models.

Interesting how ESA bills this as "good test for debris monitoring systems and fragmentation models", but had a US satellite landed anywhere in the EU, they would be holding investigations, demanding reparations, and publicly chastising NASA for poor planning and reckless disregard of human safety.

With its fins and aerodynamic shape, GOCE will maintain a stable position in orbit as it approaches entry.

Why don't they use the reaction wheels make it tumble before reentry?

Because it doesn't have reaction wheels.

Krag said that GOCE components that are the typical suspects for surviving re-entry are a tank and magnetotorquers, as the spacecraft has no reaction wheels. "The rest of the components are âunrecognizableâ(TM) incomplete, irregular fragments," he added.

Wait now... what the fuck? How is this okay? They're saying that rocket scientists cannot plan such an event? Not even a tiny weency bit of fuel in reserve for re-entry? It's totally ok to allow something to fall onto the planet, possibly killing 1 or more? What if it hits an airline? The article isn't very informative, and leaves you with the assumption that if it hits you or any of your stuff (they specified a Honda?) it's covered by The U.N., and all you have to do is get with your local government. uh

RE fuel: Not really; GOCE only has an ion engine which has nowhere near enough (instantaneous) thrust to effect a controlled re-entry (over realistic timescales)

RE prediction:Again, not really - there are too many variables; you can get a landing ellipse once re-entry has begun but before that, for a satellite this size, its really hard to get a handle on things more than a few days in advance.

Having said this, the initial article is a tad misleading, they'll be able to say pretty accurately soon if not now

Not sure what you mean, maybe I'm off beat here (out of scale?). But what I'm talking about is the liability involved with putting things into orbit, but not have a sure-fire way to determine where it's going to eventually end up, or not have some safety mechanism in place, like we do with everything else. Maybe it's a lot harder than I can imagine. But who pays the bill if shit goes tits-up, falls out of space, and hits a large airliner killing 250 people?

Shock! Horror! There is commercial insurance that covers this sort of thing. Which is priced appropriately to the risk. By people who can do the mathematics.

I'm not privy to the details of their insurance. But do a back of the thumbnail estimate :
[1] number of airplanes that have been hit by falling space debris
divided by [2] the number of airplanes that have fallen out of the sky since 1957 (Sputnik) multiplied by [3] Warsaw Convention limits on liability for an airline passenger (a couple of hundred th

I have to take flight to Asia on Sunday night, maybe I should wait until this baby hits the ground until I travel. It would probably cut the plane in half if it had a direct hit! Mama Mia is nowhere safe these days.

Which Sunday night would that be? Sunday night with respect to the ESA, Sunday night in Canada since it was a CBC article, or Sunday night where ever the satellite falls? Because Sunday night in Sydney, Australia is different than Sunday night in Seattle, Washington.

TFS mentions the times when this thing might come down, but bot the timezone those times apply to. Considering that there is a full 24 hours between extremes of timezone the window is pretty meaningless.

I know you're probably being flippant, but prior to the whole re-entry shenanigans this thing was boss. The gyros alone contain the roundest thing ever built by humans (anecdotal, from my Prof). Ridiculously fine sensing apparatus

Check out the prediction web site [n2yo.com] to see if it might land near you. Be sure to click the "show all passes" button to see the daylight passes in addition to the night passes. It calculates your lat/long from your ip address, then builds a table of overhead passes in the next 5 days. Look at the "El" column. That's the maximum degrees from the nearest horizon. If you see a number near 90 between Sunday night and Monday morning, watch out. Otherwise, rest easy.

I guess most of you weren't around when Skylab fell back to Earth [history.com]. Skylab was a much bigger satellite, but its equatorial orbit somewhat narrowed down the possible landing site locations. Everyone said it would probably fall into the sea. When pressed why, they'd admit they had no idea where it would come down. It was just that the majority of the surface area of the swath of the earth covered by Skylab's orbital inclination was ocean.